They called it a comet, 'for lack of' a better term/word. [=because they could not think of a better term/word for it]
His honesty, or 'lack thereof', is the real problem. [=the real problem is his lack of honesty]
There was 'no lack of' interest in the proposal. [=there was much interest in the proposal]
(..) or risk death. A new day and a new opportunity. The flock stay in close contact by calling one another. Weak from lack of food and water, they use thermals, rising columns of warm air, to gain height. For many this is their first journey across the Himalayas. For some, it will be their last. (..)2006 TvShow: Planet Earth Title: Mountains Season: 1 Episode 2